I really loathe OC's in the OP fandom, but I was surprised that I liked Katsu. :D I'm certain it's the way you portray him into a good fitting role :3 I approve~! And look forward to the next chapter~!

That was pretty good. And I like how you made a somewhat grand entry for Sabo. You should also mention later how Katsu got his bounty. Unless its the fact that he's the son of the Pirate King and World's Greatest Swordsman, then that would be a bit too obvious.